A giant ganglion cyst of the semimembranosus tendon: a case report.

We report a rare case of a 'giant ganglion' with 24 x 10 x 12 cm dimensions originating from the semimembranosus tendon. The patient presented with chronic pain and a palpable mass in his left calf located between the superior aspect of the popliteal fossa and the distal third of the calf. MRI revealed the mass to be a ganglion in close relation to the semimembranosus muscle at its attachment to the tibia.